APS-C Leica T type 701 to be announced in April

Started 7 months ago | Discussions thread
bosjohn
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Re: APS-C Leica T type 701 to be announced in April
In reply to brudy, 7 months ago

much cheaper labor an no r and d expenses as the Leitz patents had expired. there are simpler optical range finders that will work well enough. The Leitz design required some very careful grinding and alignment of elements so that while the concept is essentially a coincident range finder ( there are two images seen in the range finder patch and twisting the lens focusing ring brings the images together or moves them further apart, when they are superimposed over each other so you see only one image your in focus) the top and bottom edge of the range finder patch can be used like a split image range finder ( there is stationary image outside the rangefinder patch either on top or under the patch and the image in the finder patch moves accross the stationary until vertical lines are lined up) this is all happening at the same time just depends on where your eye is looking. split image finders are as much as four times more accurate but require some straight lines to work well.

in any event this was exclusive to Leitz until the patents ran out and Mamaya copied the finder with great success. I am not sure if the Cosina range finder has these features.

but bottom line is the focusing accuracy of your camera depends on the effective base ( the distance between the two image windows multiplied by the magnification of the range finder view finder. and how accurately and well made the device is and how easy clearly the two images can be seen. The leica M 3 set the standard for this but other makers now that the patents have expired make some excellent rangefinders as well. the vast majority of range finders are only coincident type which do not have clearly marked tops and bottoms to the range finder patch which will not allow for split image type alignment.

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bosjohn aka John Shick bosjohn@yahoo.com

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